Vernon Davis, Michael Turner, Jay Cutler and others have yet to hit their stride, but their teams are nonetheless moving along at a winning clip.

Plenty of NFL tight ends would be happy to switch places with San Francisco's Vernon Davis this season. The 49ers are 6-2 with a two-game lead in the NFC West and look to be in position to make another run deep into the playoffs or beyond.

But this isn't necessarily a scrapbook season for Davis, who isn't having the type of year he had in 2011.

After catching three, zero and two balls in the last three games, Davis on Thursday tweeted: "@ some point they gotta let me free like willy!"

It's not as if Davis has gone from statistical whale to minnow, but he's not the offensive focal point he once was. And in that, he's not alone. Look at the teams with the NFL's top five records — the ones with six or more victories — and each has at least one player who somehow has fallen short of expectations.

In short, the league's already good teams could be even better with a heightened contribution from these players:

Running back Michael Turner, Atlanta: The undefeated Falcons have a four-game lead in the NFC South, so they're in an enviable spot. But they can't seem to get their 24th-ranked running game going. Turner is averaging a career-low 3.8 yards per carry and has three rushing touchdowns after scoring a combined 33 over the last three seasons.

He has rushed for 100 yards once this season after six such performances last year and seven in 2010. What's more, he was arrested on suspicion of drunk driving in the hours after the Week 2 win over Denver. Memorable as this season has been for his team, this has not been a stellar year for him personally.

"I'm not sure why it's going like this," Turner told reporters last month. "It's great to be 6-0 [now 7-0] and everything. But we can't just assume we're always going to get an interception or a last-minute field goal every time. At some point, we're going to have to run the ball."

Quarterback Jay Cutler, Chicago: This hasn't been a bad season for Cutler — the Bears have lost only one game — but he hasn't been as red-hot as he was coming out of the summer.

The Bears have dug some holes for themselves, and Cutler has helped get them out. He's the league's highest-rated passer in the fourth quarter.

Still, he has yet to hit his stride on a consistent basis. A lot of that is because of Chicago's many protection breakdowns. Through seven games, Cutler has been sacked 25 times, two more than he was in 10 games last season.

And consider this: Three times this season, the Bears have opened games by dropping back to pass. On all three occasions, Cutler was sacked.

Linebacker Connor Barwin, Houston: After collecting 111/2 sacks in 2011, Barwin didn't get one this season until the Texans' win over Baltimore in Week 7. That was a big one, resulting in a safety.

Football is a team game, and the Texans have the third-ranked defense — without injured linebacker Brian Cushing — so Barwin's statistical drop-off hasn't affected the bottom line. But he's in a contract year and clearly didn't expect to go nearly half a season without getting to the quarterback.

Teammate J.J. Watt had been beating Barwin to the passer, so when Barwin finally got to Joe Flacco first…

Cornerback Corey Webster, New York Giants: Webster is the best corner on the team, but he got off to a slow start with a season-opening loss to the Cowboys, a game in which the Giants … simply weren't the Giants.

"We weren't aggressive," Webster said recently, looking back on that defeat. "We weren't putting our hands on them as a team. I didn't do it myself, but as a team, we were just kind of passive, kind of letting them dictate what they wanted to do to us, and that's not how we've been successful around here."

The Giants have given up seven passing touchdowns of 26 yards or longer, and they're ranked 26th against the pass. It hasn't helped that Webster has been hampered by hand and hamstring injuries. Lately, New York's secondary has begun to stabilize, something that will be helped by Sunday's expected return of safety Kenny Phillips.

Davis, San Francisco: The intermittent disappearance of Davis might have been a bigger problem earlier in his career, when he had a tendency to sulk and make his disappointment very evident. In Jim Harbaugh's system, Davis has emerged as an excellent pass blocker who can still make clutch catches when necessary. The 49ers also have an improved cast of receivers around him.

"I'm competitive," Davis said. "I don't let that affect me. I don't let that affect the team. … It's a good thing I'm that way because it shows I'm a competitive guy."

And when he breaks free in that offense? That's enough to give any defense the willies.